Science Inquiry Skills + Endocrine

Aim

A sentence or two that describes what the investigation is trying to achieve.

Variable 

Any factor that can be controlled, changed, or measured in an experiment.

Independent variable

ONE factor you are testing the effect of/changing to determine whether it causes a change in the dependent variable, you must remember to include the units.

Dependent variable

The factor you are observing to determine whether it changes in response to the changes in the independent variable, remember the units.

Controlled variables

The factors that will change the results of the experiment if we don’t take care to manage them carefully, so they need to be kept the same throughout the experiment. They are generally not things like the size of a test tube or temperature of the room- these things don’t really make a big difference. We like to have at least three controlled variables.

Control group

The group without the independent variable, used as a comparison or baseline.

Hypothesis

This is what you think might happen, based on your understanding of the dependent and independent variables.

A good hypothesis should be a simple, testable statement about the relationship between the independent and dependent variables.

Don’t say “I think” or “I predict” or ‘because” or “if… then…”

For example:

Increasing A decreases B.

Materials list

Dot points and specific sizes and quantities

Method

Should be a list format, in order and contain quantities. You don’t need to start with ‘collect the equipment’. Someone else should be able to follow your method and do the experiment EXACTLY as you did it.

Example:

1.     Take 6 petri dishes and label 3 salt water, 3 freshwater

2.     Line each petri dish with 4 cotton wool balls

3.     Place 10 sunflower seeds into each petri dish

4.     Water each of the 3 salt water petri dishes with 5ml of salt water

5.     Water each of the 3 fresh water petri dishes with 5ml of fresh water

6.     Place the 6 petri dishes onto the window sill where they will receive equal sunlight.

Water each day at 9am, counting the number of seeds germinated.

Rules for Diagrams

1.     Use a pencil, always.

2.     Use a ruler for all straight lines

3.     Diagram must be 2 dimensional (2D), usually a side view, no shading or depth required

4.     Use measurements if appropriate

5.     Clear (not crisscrossing) labels in pencil, label with arrows or lines, but they must touch the item they are identifying

Rules for tables

• P - Pencil

• R - Ruler

• H - Heading (overall title, column, and row titles)

• U - Units in the heading of the table

• I - Independent variable in the left-hand column

• D - Dependent variable on the top row

Graph mark allocation

1 mark                  graph title that reflects the variables (check the axes labels, they will guide you), don’t use vs.

1 mark                  correctly labelled axes with title

1 mark                  for the correct units on the axes, in brackets next to the axis title

1 mark                  correctly scaled, even axes (don’t forget to include a zero point)

1 mark                  correctly plotted data points / columns

1 mark                  joined data points / lines of best fit

Conclusion

1.     What happened

2.     hypothesis was supported? include data from your experiment?

3.     outliers in your data? outliers removed in your analysis?

4.     relationship etween your variables?

5. science concepts and theories or laws to explain the relationship found?

Validity and Reliability

R= reliability and replication (trials, calculate an average). Are you getting similar values between your trials? What can you do to improve the reliability?

 

V= validitiy, was there an uncontrolled variable that influenced the experiment. Was there something other than the independent variable affecting the outcome of the experiment (dependent variable). Low validity experiments are often associated with poor experimental design or measurement accuracy. What can you do to improve the validity?

Endocrine System

The endocrine system maintains homeostasis in living things by responding to changes in the body through the release of hormones.

Its response is slower than the nervous response, but can last a lot longer.

What is the main function of the ES?

The main function of the endocrine system is to regulate our bodily processes.

It includes:

•Glands

•Hormones

•Target cells

Hormones

Hormones are chemical substances that act as messengers in the body to influence the activity of cells.

Where are they produced?

Hormones are produced by endocrine cells of endocrine glands.

How do they move around the body?

The hormones travel through the body via the bloodstream.

What do they do?

 Hormones affect the activity of another part of the body called a target site or target cell.

Hormones and Receptors

Each hormone can only affect certain cells called target cells, which have a specific receptor for the hormone.

In order affect the cell, the hormone’s shape must be able to fit the shape of its receptor like a key going into a lock.

Endocrine Glands

Endocrine glands are locations in the body that produce hormones. 

Together all these glands form the endocrine system.

Pituitary gland

The endocrine system's most influential gland often called the master gland. Under the influence of the hypothalamus, it produces 9 hormones to regulate the function of the other endocrine glands.

Adrenal glands

A pair of endocrine glands that sit just above the kidneys and secrete hormones such as adrenalin that help arouse the body in times of stress.

Pancreas

Regulates the level of sugar in the blood by releasing insulin and glucagon.

Ovaries

Glands that produce the egg cells (ovum) and hormones such as oestrogen and progesterone

Testosterone

Male reproductive organs which produce sperm and hormones such as testosterone.

Label

Controlling Glucose levels

•Your cells also need an exact level of glucose in the blood. 

•Excess glucose gets turned into glycogen in the liver.

•This is regulated by 2 hormones (chemicals) from the pancreas called:

insulin and glucagon

Too much Glucose (+ Diagram)

If there is too much glucose in the blood, the pancreas detects this and secretes insulin. The insulin travels to receptors on the liver cells and causes these to  convert some of the glucose to glycogen.

Too little glucose (+ Diagram)

If there is not enough glucose in the blood, the pancreas detects this and secretes glucagon, which travels to receptors on the liver cells and causes the cells to  convert some of the glycogen to glucose.