Safety, Scientific Method and Experimental Design Review

  1. Why do you wear your hair back in the lab?

To prevent it from getting in the way of chemicals or a fire.

  1. Why do you wear closed toed shoes in the lab?

To protect your feet from chemical spills, cuts from broken glass or dropped utensils (scalpels)

  1. Who is ultimately responsible for your safety in the lab?

YOU!!

  1. Why do you wear goggles in the lab?

To protect your eyes

  1. Are you allowed to eat and drink in the lab?

No

  1. If you get chemicals on your skin, what do you use?

Emergency shower for 15 minutes

  1. If you get chemicals in your eyes, what do you use?

Emergency eye wash station for 15 minutes

  1. Do you point a test tube towards you or others?

No you should always point a test tube away from everyone and towards a wall.

  1. Do you put a lid on a test tube when you heat it?

No, never heat a closed container

  1. What do you do with extra chemicals you didn’t use in the lab?

Dispose of according to the MSDS

  1. What is a hypothesis? An educated guess

--It must be __testable______to make it a good hypothesis.

  1. Define Independent variable?

What we manipulate or change

  1. Define Dependent variable?

What we are measuring in an experiment

  1. A scientist thinks that temperature affects the weight of pygmy shrews.

-What is the dependent? Weight of pygmy shrews

-What is the independent? temperature

  1. What is a constant?

The things that stay the same for all groups

  1. What is a control?

The group that has all of the constants but none of the variables – what we compare everything to.

  1. When making a graph, where does the independent variable go? The dependent? (hint: think DRY MIX) Independent goes on X- Dependent goes on the Y
  1. What piece of equipment is used to measure mass?

Triple beam balance

  1. How would you measure the volume of a rock?

Use a graduated cyclinder filled with water- measure the water (at the meniscus) then drop in the rock and measure again (at the meniscus) Find the displacement by subtracting the initial from the final to find volume.

  1. What piece of equipment is used to measure volume.

Graduated cylinder or beaker

  1. What does MSDS stand for?

Material safety data sheet

  1. Why is an MSDS important?

Give s you all of the information needed for working with a chemical – fire hazards, emergency numbers, safety precautions, how to dispose it, etc.

  1. A lab requires you to smell an unknown substance. What is the correct way to do that?

Waft

  1. What are some things to reminder when working with glassware? (at least 2)

Check it for crack before beginning, NEVER use it to drink out of.

  1. If you hurt yourself in the lab, what should you do?

Immediately tell the teacher

  1. Why do we use a fume hood?

For toxic substance with smell or smoke.

  1. When using a scalpel what are two rules you need to remember?

Always cut away from you, always wear close-toe shoes

  1. A scientist conducts an experiment using twelve 35 year old women that all have brown hair. He puts them in 2 groups and tests the effects of hair growth using a new shampoo that claims to make hair grow faster and an older version of a shampoo that claims to make hair grow faster.

-What are the constants? 35 year old women with brown hair

-What would have been a good control group? Basic shampoo or no shampoo

-What is the dependent variable? Hair growth

-What is the independent variable? Growth shampoo

  1. A football coach wants to see what flavor of Gatorade makes his athletes run faster. He tests one group with orange Gatorade, group two with red Gatorade, group 3 with blue Gatorade, and group 4 with no Gatorade.

-What is the independent variable? Gatorade flavor

-What is the dependent variable? Athletes speed

-What is the control group? Group 4 – no gatorade

  1. What is the first step you should take when you receive a lab project from your teacher? READ THE DIRECTIONS!
  2. If you have known allergies who should you tell?

Teacher

  1. What is the correct for the solution to the right? 36.5 ml
  1. Define accuracy – being correct
  1. Define Precision – same results, repeatability