Spring term Y8 EoTm

end of term set deciding test

What factors affect drag forces and friction?

Drag forces and friction are influenced by the roughness of the surface, the speed of the object, its shape, and the type of fluid it moves through.

How do solid surfaces support objects?

Solid surfaces support objects by pushing upward with a force that matches the object's weight, preventing it from falling.

What is a moment in physics?

A moment in physics is the turning effect of a force applied at a distance from a pivot point, calculated by multiplying the force by the distance to the pivot.

How do you calculate the moment of a force?

To calculate the moment, multiply the force (in newtons) by the distance to the pivot point (in meters). The formula is Moment = Force x Distance.

How do fluids exert pressure?

Fluids exert pressure in all directions because their particles move and collide with surfaces, distributing the force evenly.

How does pressure affect objects in fluids?

Objects behave differently in fluids based on pressure differences; they may float or sink depending on their density relative to the fluid.

How does liquid pressure change with depth?

Liquid pressure increases with depth due to the weight of the liquid above; the deeper you go, the greater the pressure.

How do hydraulic machines work?

Hydraulic machines operate using fluids to transmit force; a small force over a small area can produce a larger force over a larger area.

What is stress in materials?

Stress in materials is the internal force per unit area that occurs when a material is pushed or pulled, potentially causing shape changes.

What is the theory of natural selection?

The theory of natural selection states that organisms well-suited to their environment are more likely to survive and reproduce, passing on advantageous traits.

Why do species evolve over time?

Species evolve due to genetic changes, environmental pressures, and natural selection, favoring traits that enhance survival and reproduction.

What is the peer review process in scientific research?

The peer review process involves experts evaluating scientific work to ensure it is valid, reliable, and contributes to scientific knowledge.

What evidence did Darwin use for his theory of natural selection?

Darwin used observations of species variations, fossil records, and geographical distribution to support his theory.

What factors can lead to extinction?

Extinction can occur due to habitat loss, climate change, overhunting, invasive species, and diseases.

Why is biodiversity important for plants and animals?

Biodiversity is vital as it maintains ecosystem stability and productivity, allowing for species adaptability to changes.

Why do some species become extinct?

Species can become extinct due to habitat destruction, inability to adapt, and competition with other species.

What is an endangered species?

An endangered species is at risk of extinction due to a declining population or habitat loss.

What techniques help prevent extinction?

Techniques to avert extinction include habitat conservation, breeding programs, legal protections, and ecosystem restoration.

How does preserving biodiversity help humans?

Preserving biodiversity benefits humans by ensuring clean air and water, crop pollination, and sources of food and medicine.

How are characteristics inherited?

Characteristics are inherited through genes passed from parents to offspring, with each parent contributing one allele for each trait.

What is the relationship between DNA, genes, and chromosomes?

DNA contains genetic information, genes are segments of DNA that code for traits, and chromosomes are DNA structures that hold many genes.

How can a DNA mutation affect an organism?

A DNA mutation may alter protein production, leading to different traits and possibly being inherited by future offspring if it occurs in germ cells.

What is the structure of DNA?

DNA has a double helix structure made of two strands of nucleotides, featuring a sugar-phosphate backbone and nitrogenous bases pairing in the center.

How did scientists discover the structure of DNA?

Scientists collaborated by sharing research and conducting experiments, leading to the discovery of the double helix by Watson and Crick.

What are dominant and recessive alleles?

Dominant alleles express their traits with one copy, while recessive alleles require two copies to show their traits.

How does a Punnett square show inheritance?

A Punnett square is a grid that predicts the genetic outcomes of offspring based on parent alleles, indicating the chances of inheriting traits.

Why are offspring not identical to their parents?

Offspring differ from parents due to genetic variation from allele combinations and potential mutations.

How is a product made using genetic modification?

Genetic modification alters an organism's DNA to enhance traits, like pest resistance or improved nutritional value.

What are some advantages of genetic modification?

Advantages of genetic modification include higher crop yields, reduced pesticide use, enhanced nutritional value, and new medicines.

What is the model of chemical change and conservation of mass?

The model shows that during a chemical reaction, atoms rearrange to form new substances, and total mass remains constant (conservation of mass).

How do you write word equations for chemical reactions?

Word equations represent chemical reactions using the names of reactants and products to show changes.

How can particle diagrams show chemical reactions?

Particle diagrams illustrate the arrangement and movement of atoms or molecules before and after a reaction, showing bond changes.

What energy transfers happen in combustion?

Combustion reactions release energy as heat and light when chemical bonds in the fuel break and form new bonds with oxygen.

What is a word equation for a combustion reaction?

An example of a combustion word equation is: Methane + Oxygen → Carbon Dioxide + Water.

What do particle diagrams show in combustion reactions?

In combustion reactions, particle diagrams display the interaction of fuel molecules with oxygen, resulting in carbon dioxide and water.

How do you predict the products of combustion?

To predict combustion products, identify the fuel and oxygen, expecting carbon dioxide and water as typical products.

What is thermal decomposition?

Thermal decomposition is a reaction where a compound breaks down into simpler substances when heated.

What is a word equation for a decomposition reaction?

An example of a decomposition word equation is: Calcium Carbonate → Calcium Oxide + Carbon Dioxide.

What do particle diagrams show in decomposition reactions?

Particle diagrams for decomposition show how a compound disassembles into its components.

How do you predict the products of decomposition?

To predict decomposition products, examine the reactant to determine what simpler substances it can yield when heated.

What is conservation of mass?

Conservation of mass states that in a closed system, the mass of reactants equals the mass of products in a chemical reaction.

What observations can be made about mass in changes?

Observations about mass in chemical or physical changes indicate that mass remains constant, as no atoms are lost or gained.

How do you calculate masses in a chemical reaction?

Masses can be calculated using a balanced chemical equation to determine molar ratios, applying the conservation of mass.

How do you balance symbol equations in reactions?

Balancing symbol equations involves ensuring the same number of atoms for each element is present on both sides of the equation.

What are exothermic and endothermic changes?

Exothermic changes release energy to the surroundings, while endothermic changes absorb energy from the surroundings.

How can you tell exothermic and endothermic reactions apart?

Exothermic reactions can be recognized by a temperature rise, while endothermic reactions show a temperature drop.

How do energy level diagrams show reactions?

Energy level diagrams illustrate that exothermic reactions result in lower-energy products than reactants, and endothermic reactions have higher-energy products.

How do energy level diagrams explain energy changes?

Energy level diagrams depict energy changes during phase transitions and chemical reactions, revealing energy absorption or release.

What happens to chemical bonds during reactions?

During exothermic reactions, chemical bonds form and release energy; in endothermic reactions, bonds break and require energy input.

How do bond energies explain energy changes in reactions?

Bond energies indicate that breaking bonds requires energy while forming bonds releases energy, influencing overall energy changes in reactions.