Complete the risk assessments Hazard Risk Control measures Hot apparatus (eg. tripod, bench lamps) Use with care on a tile. Cut away from fingers. Water and electrical equipment (eg lamps)

ANSWERS: Risk assessments Hazard Risk Control measures Hot apparatus (eg. tripod, lamps) Skin burns Touch cool base only Sharp scalpel Cut skin Use with care on a tile. Cut away from fingers. Water and electrical equipment (eg lights) Electric shock Dry hands before touching switch. Keep water well away from plug/switch

Hypothesis tips A hypothesis states what you think is going to happen in the experiment. A hypothesis should link the independent and dependent variables.

Hypothesis practise “A student did an investigation to see the effect of different amounts of fertiliser on leaf size in bean plants.” What is the independent variable? What is the dependent variable? Write a hypothesis for this experiment.

Hypothesis practise “A student did an investigation to see the effect of different amounts of fertiliser on leaf size in bean plants.” What is the independent variable? Amount of fertiliser What is the dependent variable? Leaf size Write a null hypothesis for this experiment. “The higher the amount of fertiliser, the larger the bean leaf size”

Explaining your hypothesis “The higher the amount of fertiliser, the larger the bean leaf size” Explain the hypothesis….

Explaining your hypothesis “The higher the amount of fertiliser, the larger the bean leaf size” Explain the hypothesis…. Plants will absorb the mineral ions in the fertiliser through their roots and use it to help make new proteins, allowing them to grow.

Graph tips Use an even scale that allows you to plot accurately to nearest 1mm. (avoid scales like 0, 7, 14, 21 OR 0, 3, 6, 9, 12) Each scale should occupy at least 1/3 of the paper. Show clear headings and units (note m is NOT suitable for minute) Draw a suitable line (if the data is continuous)

New info’ Sketch graphs A sketch graph can be drawn to show the basic pattern present in your data…. Rate of reaction Temperature

Sketch graph tips Full headings on each axis. Units are not required New info’ Sketch graph tips Full headings on each axis. Units are not required No scale values are needed Draw the line carefully, so that the trends in the data are clear.

Draw a sketch graph of these results apply Draw a sketch graph of these results Carbon dioxide added / % Time for lettuce to grow to harvest size / days 52 0.2 41 0.4 32 0.6 29 0.8 Extension: How can a farmer boost carbon dioxide levels in a greenhouse?

Discuss in your groups where the 3 marks will be awarded. recall Were there any anomalies? Explain your answer. (3 marks) Discuss in your groups where the 3 marks will be awarded.

Were there any anomalies? Explain your answer. 1. Anomalies are points that do not fit the pattern. 2. They lie away from the line of best fit. 3. All points lie on the line, so no anomalies are present.

Discuss. What key difference would be in your answer if the graph looked like this?

Were there any anomalies? Explain your answer. Anomalies are points that do not fit the pattern. They lie away from the line of best fit. The point at 0.5 % CO2 is far from the line of best fit, so is an anomaly. (The time to grow was too long, 40 days instead of 30).

How to use repeat readings New info’ How to use repeat readings Often during an investigation, if there is time, you will carry out repeat readings. Repeat readings can be used to help identify and remove anomalies. This allows the calculation of the mean.

Use the repeat readings to get more accurate results. Temperature of reaction / °C Time for reaction /sec Test Repeat 1 Repeat 2 20 200 210 207 30 158 162 168 40 45 110 117 apply

Using repeat data to get more accurate results Temperature / °C Time for reaction /sec Mean time .…/ sec Test 1 Test 2 Test 3 20 200 210 207 206 30 158 162 168 163 40 (45) 110 117 114